RFI Eng response notice items 4-19 MCU150111

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Item 5. Provide updated traffic report for the current proposal including any additional traffic generation
associated with the increased development on the site. The updated report should also investigate any the
required upgrade works on the external roads and road intersections in accordance with current applicable
standards and traffic data.

Our Response

Calibre Consulting has prepared a Traffic Impact Assessment Report No. B14158ER02 (attached) this report indicates:

    •    The additional traffic generation associated with the increased development on the site is 28vph during peak
         hour periods

    •    Based on the assessment of the network it is concluded that the road links and intersection arrangements as
         proposed will be able to accommodate the anticipated traffic volumes to at least the ultimate design year of
         2028. The forecast demand estimates are based on the ultimate development scenario as outlined above.

    •    The key finding of this traffic impact assessment is that the proposed intersection treatments and infrastructure is
         sufficient to support the proposed development, which was previously approved in the earlier site development
         approvals (Refer Council’s DA Ref No: 132007.2398.02). There are no adverse impacts anticipated as a result of
         the development traffic generated by the expanded developable site area. Based on the analysis there are no
         further mitigation measures proposed.

    •    The current level of design detail available for this DA phase shows that the proposed development layout is
         compliant with the relevant State Planning Codes.


Item 6. Provide information and updated drawing/s of the development site to indicate the proposed earthworks
and finish levels including but not limited to the following:
(a) Relevant cross sections and details to depict the extent and the changes to the surface levels.
(b) Any required earth retention works (eg retaining walls, batters) particularly for the eastern part of the site eg
near the proposed club house, proposed basins and the retained house and shed on proposed Lot 101.

Our Response

Calibre Consulting has prepared concept bulk earthwork drawings (attached 15-001261 sheets SK102 to SK106). These
plans indicate changes to surface levels and retaining walls.



Item 7
    (a) Stormwater runoff rates from the developed site must be maintain to its predevelopment rates for all
        storm events up and including 100 years storm event and taking into consideration the retention
        capacities of dams exist on site prior to the development works.

Our Response

Previous approved analysis for this site was undertaken for all return intervals and as per ARR 1987, that is modelling of
a range of storm burst. It was determined that for all Return Intervals the developed flows were below predevelopment
flow rates (refer Table 3-9 in report B14158.W-03A). It was assumed that storms prior to the peak storm burst have filled
the existing dams to their capacity. This is considered standard practice for flood studies.

As requested by Council further analysis was undertaken to assess possible impact of the volume of the dams. We have
compared the volume of dams (if empty) to the volume of the inflow hydrograph. Analysis has been diagrammatically
represented for the four (4) existing dams, for the 1 yr ARI and 100yr ARI critical storms, refer to attachments A and B.
Analysis has shown for a 1 yr ARI and 100yr ARI storm event the dam volumes equate to 1.1% and 0.4% of the inflow
hydrograph volume respectively. In reality the percentage will be lower as the dam will not be empty as the storm burst
commences. Therefore, the dams will be filled significantly before the peak site flow and have no impact on the existing
flow of the site.